1. Don't ambush them or attack them/body slam them 

I did this the other day to one of my friends when I saw him standing across the road. We had this brief moment when we just kind of ran at each other and body slammed each other and just walked away. I would not recommend doing this to someone unless you know them very well because otherwise they might punch you.

2. Don't yell at them from across a big room or a field

I would not recommend doing this because it could be potentially embarrassing for your friend or whomever you are calling over. This could be bad to do to someone who doesn't like to have attention called to them. This could also cause the person to ignore you and not say hi back which would embarrass you.

3. Don't call them by a weird nickname in front of people who don't know you or the nickname

This could again totally embarrass them and you, which if you do this in front of people you don't know very well, could make the rest of your interactions super awkward. This could make your friend mad at you for sharing a secret nickname with the rest of the world. It also makes you seem weird and like you don't know their correct name.

4. Don't do something weird when you say hi to someone you don't know very well

For example, don't act like you've know them you're whole life. You should definitely act like you've known them for a long time because that makes people feel comfortable around you, just don't make it uncomfortable.

5. Don't wave like a maniac when you see them across the room 

You should definitely wave to someone you know, but you shouldn't wave your arms around like you are a bird or like you have no control of your arms.

6. You shouldn't act like you don't know someone if you do know them 

Something you should not do, is ignore the people you know because then you make things awkward between you two. You should say hi or wave or just acknowledge them. Don't be weird.

7. Don't call at them using a bird call 

This can make things awkward if they don't know it's coming and they won't usually know how to respond.

8. Don't try to hug someone you don't know very well especially when they don't want a hug

This can make for some awkward interactions and some people don't like to be touched. Make sure that the person knows that you want to hug them before you do so you don't accidentally get punched.

9. Don't do the handshake/hug thing

This is a very confusing thing that happens when you first meet someone and it can be weird and then you just end up hugging a fist. Don't hug a fist

10. ​DO​ be normal and do normal things

You should shake someone's or hug them when it feels right. You should wave if you know them. The most important thing to remember is to use good eye contact.